While it is very common for portal-based user interfaces to include information delivered from external providers, a number of issues occur when such interfaces are interacting with an application associated with different domain. In one instance, there is a primary server providing the overall user interface experience and a secondary server that provides content in the user interface. Conventional rich Internet technologies prevent communication from a domain that is different from the primary server. Normally communication is performed by dispatching events through a proxy to give the appearance of originating from the same domain as the primary server. The secondary server and the primary server often communicate by dispatching events through the proxy. This is commonly known as cross-domain communication. However, various problems become apparent when implementing cross-domain communication in practice. Real-world environments can frustrate mechanisms to secure cross-domain communications because, for example, malicious code can infect the primary server or a client device displaying the user interface and cause significant harm. The malicious code may propagate throughout a network and infect other devices and systems. Even when the secondary server is a trusted resource, each domain in that resource requires a code change in the primary application and/or a separate event handler, which can impede product development.